1. Field of the Invention
The invention relates generally to stacked-type, multi-flow heat exchangers. More specifically, the invention is directed towards stacked-type, multi-flow heat exchangers for use in an air conditioning system of a vehicle.
2. Description of Related Art
Referring to FIGS. 15-17, a known stacked-type, multi-flow heat exchanger may comprise a plurality of heat transfer tubes 70 and a plurality of outer fins 71, such that heat transfer tubes 70 and outer fins 71 may be alternately stacked. Heat transfer tubes 70 may comprise a first tube plate 72, a second tube plate 73 connected to first tube plate 72, and an inner fin 74 having a wave-shape and extending in a longitudinal direction between first tube plate 72 and second tube plate 73. In such a known stacked-type, multi-flow heat exchanger, when a heat exchange medium, e.g., a refrigerant, is introduced into heat transfer tube 70, the heat exchange medium flows through a plurality of independent paths 75 formed by an interior wall of heat transfer tube 70 and inner fin 74. Moreover, energy in the form of heat is exchanged between air passing through the outside of heat transfer tube 70 and the heat exchange medium.
Nevertheless, because paths 75 are formed independent of one another, the heat exchange medium flowing through one path 75 does not mix with the heat exchange medium flowing through another path 75. Consequently, a heat exchange efficiency of such a known stacked-type, multi-flow heat exchanger may be reduced. Further, as shown in FIG. 17, when such a known stacked-type, multi-flow heat exchanger is used as an evaporator, residual water 77 may be retained at drainage groove portions 76 formed between heat transfer tube 70 and outer fins 71. As such, water 77 may not be properly discharged from drainage groove portions 76.
Japanese (Unexamined) Patent Publication No. H04-155191 describes another known stacked-type, multi-flow heat exchanger which includes offset fins. Each offset fin comprises a plurality of inner fins having a repeating square wave shape. Because of the shape of the inner fins, when the heat exchange medium is introduced in the heat transfer tube, the heat exchange medium flowing through one path mixes with the heat exchange medium flowing through another path. Nevertheless, in such a known stacked-type, multi-flow heat exchanger, because of the shape of the inner fin, the resistivity of the path through which the heat exchange medium flows may increase, and the manufacturing cost of the heat exchanger may increase.
Therefore, a need has arisen for stacked-type, multi-flow heat exchangers that overcome these and other shortcomings of the related art. A technical advantage of the present invention is that the efficiency of heat transfer between air passing through the outside of the heat transfer tube and the heat exchange medium may increase without substantially increasing the resistivity of the path through which the heat exchange medium flows. Another technical advantage of the present invention is that the efficiency of heat transfer may increase without substantially increasing the cost of manufacturing the stacked-type, multi-flow heat exchanger. Yet another technical advantage of the present invention is that when the stacked-type, multi-flow heat exchanger is used as an evaporator, substantially all of the water may be discharged from drainage groove portions formed between the heat transfer tube and the outer fins.
According to an embodiment of the present invention, a stacked-type, multi-flow heat exchanger is described. The heat exchanger comprises a plurality of heat transfer tubes. Each of the heat transfer tubes comprises a first tube plate and a second tube plate connected to the first tube plate, such that the first tube plate and the second tube plate form a refrigerant path within the heat transfer tube. Each of the heat transfer tubes also comprises an inner fin having a wave shape positioned within the refrigerant path and extending in a longitudinal direction along the refrigerant path, and the heat exchanger also comprises a plurality of outer fins. Moreover, the plurality of outer fins and the plurality of heat transfer tubes are stacked alternately. The heat exchanger further comprises a plurality of projection portions formed on at least one of the first tube plates and at least one of the second tube plates, such that the projection portions project into the refrigerant path and extend in an oblique direction relative to the inner fin. Further, the inner fin is connected to the plurality of projection portions.
According to another embodiment of the present invention, a stacked-type, multi-flow heat exchanger is described. The heat exchanger comprises a plurality of heat transfer tubes, each of which comprises a tube plate. The tube plate comprises a flange portion positioned along a center axis of the tube plate, such that when the tube plate is folded, the flange portion forms a refrigerant path within the heat transfer tube. Each of the heat transfer tubes also comprises an inner fin having a wave shape positioned within the refrigerant path and extending in a longitudinal direction along the refrigerant path. The heat exchanger also comprises a plurality of outer fins, and the plurality of outer fins and the plurality of heat transfer tubes are stacked alternately. The heat exchanger further comprises a plurality of projection portions formed on at least one of the tube plates, such that the projection portions project into the refrigerant path and extend in an oblique direction relative to the inner fin. Further, the inner fin is connected to the plurality of projection portions.
Other objects, features, and advantages of the present invention will be apparent to persons of ordinary skill in the art in view of the following detailed description of the invention and the accompanying drawings.